1. Field of the Invention
The present invention relates to a plate producing apparatus. More particularly, the present invention relates to a plate producing apparatus capable of recording images on plates which are accommodated in a plurality of cassettes, the images being received from an image processing device.
2. Related Art Statement
Printing of color printed materials is achieved by transferring images of a plurality of colors onto a single piece of printing paper. The transfer of the respective color images is realized by using plates. Plates of Y (Yellow), M (Magenta), C (Cyan), and K (Kuro, i.e., xe2x80x9cblackxe2x80x9d) are commonly employed for color printing. In addition or in the alternative to these color plates, plates of special colors may be used. For example, printing may be performed by adding special colors to the four basic colors of Y, M, C, and K, or using the special colors alone. In the following description, a plurality of plates which are used in superposition to make one printed material are referred to as a xe2x80x9cset of platesxe2x80x9d. (Note, however, that the present invention is also applicable to single-color printing. In that case, a xe2x80x9cset of platesxe2x80x9d should be interpreted to mean a single plate).
In order to produce plates, an image recording apparatus of a so-called CTP (Computer To Plate) type, which records images directly on plates such as PS plates (Presensitized Plates) may be employed. This type of image recording apparatus irradiates each plate with a light beam which has been modulated in accordance with the image data for that plate, whereby desired images are recorded on the respective plates.
In order to realize automatic feeding of plates to an image recording apparatus, cassettes for accommodating plates and a mechanism for feeding the plates from the cassette to the image recording apparatus are required. Japanese Patent Laid-Open Publication No. 2000-351460 discloses an example of a plate feeding apparatus which feeds plates to an image recording apparatus. The disclosed plate feeding apparatus moves one of a plurality of cassettes along a horizontal direction, and further brings up or down the cassette thus moved, to a position for feeding plates to an image recording apparatus. Thereafter, the plate feeding apparatus feeds the plates from the cassette which is in the predetermined position to the image recording apparatus, and ejects the slip sheets which are inserted between the plates.
On the other hand, image data representing images to be recorded on the plates is supplied from a raster image processor (hereinafter referred to as a xe2x80x9cRIPxe2x80x9d), which operates independently from the image recording apparatus. Also supplied from the RIP is the information which is used when selecting a cassette (referred to as xe2x80x9ccontrol informationxe2x80x9d, e.g., information representing the size and thickness of a given plate). A set of plates usually comprises the same type of plates, and hence the plates are usually fed from a single cassette. Conventionally, control information associated with a given set of plates is transmitted from the RIP to the image recording apparatus as common control information to all plates, even before the transmission of the image data (see FIG. 7).
However, a conventional image recording apparatus has the following problem. The apparatus begins the preparation for a set of plates only after the image recording for a previous set of plates is completed. Therefore, if the latter set of plates is of a different type from the previous set of plates, an exchange of cassettes must be performed, which can only be performed after the image recording for the previous set of plates is completed. As a result, a wait time must be observed before the feeding of the latter set of plates can be begun. As such, the image recording apparatus cannot be utilized to its full capacity.
Therefore, an object of the present invention is to provide a plate producing apparatus having an improved plate producing ability, such that only a minimum wait time needs to be observed before a plate feeding can occur.
The present invention has the following features to attain the object above.
A first aspect of the present invention is directed to a plate producing apparatus for recording an image on plates retrieved from a plurality of cassettes based on image data transmitted from an image processing device, comprising: a cassette selection assembly for selecting one of the plurality of cassettes; a plate feeding assembly for retrieving a plate from the selected cassette; an image recording assembly for performing an image recording for the plate fed by the plate feeding assembly, based on the image data transmitted from the image processing device; and a control assembly for controlling the cassette selection assembly and the plate feeding assembly, wherein, at least before the image recording performed for the plate by the image recording assembly is completed, the control assembly obtains control information associated with a next plate and causes the cassette selection assembly to begin operating.
Thus, according to the first aspect, a cassette selection process for a next plate can be begun during an image recording for a current plate. Thus, a wait time to await the feeding of a plate in the image recording assembly can be reduced from that which is conventionally required, whereby the overall plate producing ability of the apparatus is enhanced.
According to a second aspect based on the first aspect, the control information is information which is supplied with respect to each plate from the image processing device to the control assembly.
Thus, according to the second aspect, control information is supplied with respect to each plate. This allows different attributes to be set for different plates.
According to a third aspect based on the second aspect, the plate feeding assembly feeds the plate to a neighborhood of the image recording assembly.
Thus, according to the third aspect, the distance between the plate feeding assembly and the image recording assembly can be minimized, so that the time required for loading a plate from the plate feeding assembly to the image recording assembly can also be minimized.
According to a fourth aspect based on the third aspect, the control assembly receives the control information associated with the next plate from the image processing device at least a predetermined time before a point of completion of the image recording for the plate, the predetermined time being equal to a sum of a time required for the cassette selection assembly to perform a cassette selection operation for the next plate and a time required for the plate feeding assembly to feed the next plate.
Thus, according to the fourth aspect, the plate has already been supplied to the neighborhood of the image recording assembly when the image recording for the previous plate is completed. Thus, the wait time in the image recording assembly can be further reduced.
According to a fifth aspect based on the fourth aspect, the control assembly determines whether or not to perform an exchange of cassettes based on the control information, and selectively causes the cassette selection assembly to begin operating based on a result of the determination.
Thus, according to the fifth aspect, the cassette selection assembly is operated only when an exchange of cassettes is necessary. As a result, unnecessary movements of cassettes are prevented, thereby reducing the occurrences of troubles in the cassette selection assembly.
According to a sixth aspect based on the fourth aspect, the image recording assembly comprises: an exposure section having a recording drum for irradiating the plate mounted on the recording drum with a light beam which is modulated in accordance with the image data transmitted from the image processing device; a plate loading section for mounting the plate fed from the plate feeding assembly on the recording drum; and a plate unloading section for releasing the plate from the recording drum after the image recording by the exposure section is performed for the plate.
According to a seventh aspect based on the first aspect, the control information is supplied from the image processing device to the control assembly with respect to each of a set of plates which are used to make one printed material, and, at least before the image recording performed for a non-last plate in the set by the image recording assembly is completed, the control assembly obtains control information associated with a next plate in the set and causes the cassette selection assembly to begin operating.
According to an eighth aspect based on the first aspect, the control information is supplied from the image processing device to the control assembly with respect to each of a set of plates which are used to make one printed material, and, at least before the image recording performed for a last plate in the set by the image recording assembly is completed, the control assembly obtains control information associated with a first plate in a next set and causes the cassette selection assembly to begin operating.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.